/*
 * Copyright (C) 2015 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.polaris.core.javapoet;

import java.io.IOException;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;

import javax.lang.model.SourceVersion;
import javax.lang.model.element.Modifier;

import static io.polaris.core.javapoet.Util.checkArgument;
import static io.polaris.core.javapoet.Util.checkNotNull;
import static io.polaris.core.javapoet.Util.checkState;

/** A generated field declaration. */
public final class FieldSpec {
	public final TypeName type;
	public final String name;
	public final CodeBlock javadoc;
	public final List<AnnotationSpec> annotations;
	public final Set<Modifier> modifiers;
	public final CodeBlock initializer;

	private FieldSpec(Builder builder) {
		this.type = checkNotNull(builder.type, "type == null");
		this.name = checkNotNull(builder.name, "name == null");
		this.javadoc = builder.javadoc.build();
		this.annotations = Util.immutableList(builder.annotations);
		this.modifiers = Util.immutableSet(builder.modifiers);
		this.initializer = (builder.initializer == null)
			? CodeBlock.builder().build()
			: builder.initializer;
	}

	public boolean hasModifier(Modifier modifier) {
		return modifiers.contains(modifier);
	}

	void emit(CodeWriter codeWriter, Set<Modifier> implicitModifiers) throws IOException {
		codeWriter.emitJavadoc(javadoc);
		codeWriter.emitAnnotations(annotations, false);
		codeWriter.emitModifiers(modifiers, implicitModifiers);
		codeWriter.emit("$T $L", type, name);
		if (!initializer.isEmpty()) {
			codeWriter.emit(" = ");
			codeWriter.emit(initializer);
		}
		codeWriter.emit(";\n");
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) return true;
		if (o == null) return false;
		if (getClass() != o.getClass()) return false;
		return toString().equals(o.toString());
	}

	@Override
	public int hashCode() {
		return toString().hashCode();
	}

	@Override
	public String toString() {
		StringBuilder out = new StringBuilder();
		try {
			CodeWriter codeWriter = new CodeWriter(out);
			emit(codeWriter, Collections.emptySet());
			return out.toString();
		} catch (IOException e) {
			throw new AssertionError();
		}
	}

	public static Builder builder(TypeName type, String name, Modifier... modifiers) {
		checkNotNull(type, "type == null");
		checkArgument(SourceVersion.isName(name), "not a valid name: %s", name);
		return new Builder(type, name)
			.addModifiers(modifiers);
	}

	public static Builder builder(Type type, String name, Modifier... modifiers) {
		return builder(TypeName.get(type), name, modifiers);
	}

	public Builder toBuilder() {
		Builder builder = new Builder(type, name);
		builder.javadoc.add(javadoc);
		builder.annotations.addAll(annotations);
		builder.modifiers.addAll(modifiers);
		builder.initializer = initializer.isEmpty() ? null : initializer;
		return builder;
	}

	public static final class Builder {
		private final TypeName type;
		private final String name;

		private final CodeBlock.Builder javadoc = CodeBlock.builder();
		private CodeBlock initializer = null;

		public final List<AnnotationSpec> annotations = new ArrayList<>();
		public final List<Modifier> modifiers = new ArrayList<>();

		private Builder(TypeName type, String name) {
			this.type = type;
			this.name = name;
		}

		public Builder addJavadoc(String format, Object... args) {
			javadoc.add(format, args);
			return this;
		}

		public Builder addJavadoc(CodeBlock block) {
			javadoc.add(block);
			return this;
		}

		public Builder addAnnotations(Iterable<AnnotationSpec> annotationSpecs) {
			checkArgument(annotationSpecs != null, "annotationSpecs == null");
			for (AnnotationSpec annotationSpec : annotationSpecs) {
				this.annotations.add(annotationSpec);
			}
			return this;
		}

		public Builder addAnnotation(AnnotationSpec annotationSpec) {
			this.annotations.add(annotationSpec);
			return this;
		}

		public Builder addAnnotation(ClassName annotation) {
			this.annotations.add(AnnotationSpec.builder(annotation).build());
			return this;
		}

		public Builder addAnnotation(Class<?> annotation) {
			return addAnnotation(ClassName.get(annotation));
		}

		public Builder addModifiers(Modifier... modifiers) {
			Collections.addAll(this.modifiers, modifiers);
			return this;
		}

		public Builder initializer(String format, Object... args) {
			return initializer(CodeBlock.of(format, args));
		}

		public Builder initializer(CodeBlock codeBlock) {
			checkState(this.initializer == null, "initializer was already set");
			this.initializer = checkNotNull(codeBlock, "codeBlock == null");
			return this;
		}

		public FieldSpec build() {
			return new FieldSpec(this);
		}
	}
}
